More Americans living 100 years or longer these days

You might have noticed that TV weatherman Willard Scott's morning roll call of people celebrating 100-plus years on the planet seems to grow longer and longer.

According to the U.S. Census, the number of American centenarians has roughly doubled in the past 20 years to about 72,000 and is projected to at least double again by 2020. (The same experts, however, also say that that might be a conservative guess.)

Linda J. Van Eldik, director of the Sanders-Brown Center on Aging at the University of Kentucky, said several factors have contributed to the longevity.

First, Americans as a whole are living longer. The average life expectancy has gone from 49 at the turn of the 20th century to 78 in 2012.

Also, she said, medical advances have made it possible to routinely cure diseases that once were fatal.

Van Eldik said there appear to be some common traits among those who live the longest. Many of them, she said, "follow a series of good health habits" such as exercising and eating a balanced diet.

She said a positive personality seems to be another common thread.

"They seem to have an increased level of happiness," she said. That doesn't mean that life has not thrown centenarians their share of tough times. But, she said, they seem to have an ability to come back after difficulties with a continued positive outlook.

With the first baby boomers having turned 65 last year, she said, that demographic tidal wave is likely to change a lot about how seniors are seen and treated for the better, although it also will create health challenges.

Sanders-Brown is a major force in research on Alzheimer's. Van Eldik said the percentage of American families dealing with Alzheimer's and other forms of dementia will continue to grow, increasing the demand for services for that population.

People who have reached ages 95 to 100 without serious complications of dementia will probably be OK, she said.

And, she said, there is good news for those who are decades away from hitting the 100 mark. It's never too late to start good habits that can contribute to a long, healthy life, or to help the older folks you love make the most of their time.

Obviously, exercise and diet are important. But exercise doesn't need to mean preparing for a marathon, she said. Chair exercises or a walk are simple exercises that most people are able to handle.

It's also important for all of us, especially senior citizens, to stay intellectually engaged, she said. That includes trying new things. Again, she said, it doesn't have to be something on a grand scale. It could be something as simple as trying out a new restaurant, reading a new author or mastering a new technology, such as an iPad.

Another important tool, she said, is staying socially engaged. Play cards or mahjong, go out to lunch, visit with family, volunteer or go shopping with friends.

Put these tips into action, and the Willard Scott of the future might have a special birthday message for you.